1. Field of the Invention
The present invention relates to a member for office machines. More particularly, the present invention pertains to a member for office machines which has a high friction coefficient, and is well suited for use in electrophotographic equipment and electrostatic recording equipment such as copying machines, laser printers and facsimile equipment, and further for use, as a paper feeding member, in machinery and equipment having a variety of paper feeding mechanisms such as ink-jet printers, automatic teller machines (ATM) money exchange machines, counting machines, automatic vending machines and cash dispensers (CD).
2. Description of the Related Arts
There is employed a member for office machines such as a roller and a belt in electrophotographic equipment and electrostatic recording equipment such as copying machines, laser printers and facsimile equipment, and further in such equipment as electrifying equipment, transfer equipment, developing equipment, deelectrifying equipment, paper feeding equipment and cleaning equipment.
Of these members, the paper feeding member which feeds sheets of paper by taking advantage of friction of a rubber roller or the like, is required to have excellent paper feeding characteristics, antifouling properties against paper, films and photographic printing paper, favorable durability and the like properties. Thus there have been proposed paper feeding members with various shapes and/or constructional materials.
There have heretofore been employed, for the aforesaid paper feeding members, vulcanized rubber such as silicone rubber, polyurethane rubber, styrene/butadiene rubber, butadiene rubber and ethylene/propylene rubber. In addition, attention has been paid in recent years to thermoplastic elastomers, which have come into use in combination with a softening agent.
Moreover, there has recently been brought into use, a paper feeding member in which a rubbery elastic body layer is installed on the peripheral surface of a core body having a cross-section in the form of a segment (including the form of spherical roller) or an eccentric core body.
In the case where the aforesaid paper feeding member is rotated, there are formed both a portion out of contact with paper sheets and a portion in contact with paper sheets. The paper feeding is carried out by the friction between the rubbery elastic body layer and the paper sheets when the peripheral surface of the layer comes in contact with the paper sheets. On the other hand, when the peripheral surface of the layer is out of contact with the paper sheets, the paper feeding member runs idle, thereby failing to feed paper sheets. The above-mentioned paper feeding member having such a feeding mechanism is imparted with excellent paper feeding characteristics including the capability of preventing double feeding and steadily feeding paper sheets.
In order that the above-mentioned paper feeding member may maintain stable paper feeding characteristics by taking advantage of friction of a rubbery elastic body layer, it is required to minimize variation in the friction coefficient thereof with the lapse of time (that is, an increase in the number of paper feeding times).
In general, however, the paper feeding member composed of the foregoing materials frequently brings about such an unfavorable circumstance that powders of silica, calcium carbonate, etc. and/or fibrous paper powders adhere to the surfaces of the paper feeding member during use, whereby the friction coefficient is lowered, thus making it impossible to steadily feed paper sheets. The aforesaid disadvantage tends to frequently occur particularly at the time of using reclaimed paper or art paper to be used for carrying out high quality printing.
For the purpose of preventing such disadvantage and inconvenience, there have heretofore been adopted several methods in which (1) the surface layer of the paper feeding member is abraded at every time of paper feeding so that the friction coefficient of the surface approaches the initial value; (2) a convex portion is provided on the surface of the member so as to impart a driving force to paper sheets; (3) a material having a high friction coefficient is used as the material for the member so that a moderate friction coefficient and paper sheet transport capacity are preserved even after the lowering of the friction coefficient due to the adhesion of paper powders and the like; (4) the tacky adhesion of the member surface is suppressed so as to alleviate the adhesion of paper powders.
Nevertheless at the present time, the method (1) brings about the problem that the capacities of paper feeding and transport are lowered and further, the service life of the member itself is inevitably shortened; and the foregoing methods (2) to (4) fails to exert sufficiently satisfactory working effect.